inputs:
{ config, lib, pkgs, ... }:
let
  inherit (pkgs.stdenv.hostPlatform) system;
  cfg = config.services.birdtown-visit-counter;
  inherit (lib) types mkOption mkIf;
  package = inputs.self.packages."${system}".birdtown-visit-counter;
in {
  options.services.birdtown-visit-counter = {
      enable = mkOption {
        type = types.bool;
        default = false;
      };
      listenPort = mkOption {
        type = types.int;
        default = 11567;
      };
    };
  config = {
    users.users.birdtown-visit-counter = {
        group = "birdtown-visit-counter";
        home = "/var/lib/birdtown-visit-counter";
        isSystemUser = true;
        createHome = true;
      };
      users.groups.birdtown-visit-counter = { };

      systemd.services.birdtown-visit-counter = {
        after = [ "network.target" ];
        wantedBy = [ "multi-user.target" ];
        serviceConfig = {
          ExecStart = "${package}/bin/birdtown-visit-counter -addr :${cfg.listenPort} -file visits.json";
          User = "birdtown-visit-counter";
          Group = "birdtown-visit-counter";
          WorkingDirectory = "/var/lib/birdtown-visit-counter";
        };
      };

      systemd.timers.birdtown-visits-saver = {
        wantedBy = [ "timers.target" ];
        timerConfig = {
          OnBootSec = "10m";
          OnUnitActiveSec = "10m";
          Unit = "birdtown-visits-saver.service";
        };
      };

      systemd.services.birdtown-visits-saver = {
        script = ''
          set -eu
          if ${pkgs.curl}/bin/curl http://localhost:${cfg.listenPort}/visits > visits-new.json; then
             cp visits-new.json "$(date +"%Y-%m-%d-%H-%M").json"
             mv visits-new.json visits.json
           fi
        '';
        serviceConfig = {
          Type = "oneshot";
          User = "birdtown-visit-counter";
          Group = "birdtown-visit-counter";
          WorkingDirectory = "/var/lib/birdtown-visit-counter";
        };
      };
  };
}